Blade member for fluid pump

ABSTRACT

The object is to obtain reasonably a blade member for a pump having superior fluid transporting performance. A blade member for a fluid pump includes a cylindrical portion formed around a rotational axis, a plurality of base portions protruding radially outwardly of the rotational axis from one end portion of the cylindrical portion along the rotational axis and provided along a circumferential direction, a bent portion bent from each of the respective base portion in one direction along the rotational axis, and a hole portion provided in a border portion between root portions of the adjacent base portions. A rising edge portion extending from the hole portion to a leading end of the bent portion and an overhang edge portion extending from the hole portion to a leading end of the base portion are formed by a common cut portion.

TECHNICAL FIELD

The present invention relates to a blade member for use in e.g. a water pump which serves to circulate cooling water to an engine of an automobile for example. More particularly, the invention relates to a blade member having a cylindrical portion to be mounted on a rotational shaft and a plurality of blade portions protruding radially from the cylindrical portion, the cylindrical portion and the blade portions being formed by bending a single plate member.

RELATED ART

A blade member described above draws in, in association with its own rotation, an amount of fluid in a direction of a rotational axis and applies a centrifugal force to this fluid for causing it to flow toward an outer circumference of the blade member. In an engine of an automobile, if power loss occurs in such water pump, this can cause reduction in fuel consumption efficiency of the entire vehicle. Therefore, there have been devised various means for minimizing such power loss, such as increase of the number of blade members.

Such blade member as described above is often manufactured through a punching operation or a pressing operation effected on a work comprised of a single metal plate. Yet, in such operation, there is a need to avoid interference between a working tool and the work or to secure a pressing margin for the working tool. Thus, an operational restriction is imposed on the shape of the blade member to be obtained. For instance, in the case of a bending operation to be effected on a leading end of the blade member, once the number of the blade portions to be provided along the circumferential direction of the single work has been decided, this specifies an area available as the portion to be bent. In such case, there will occur a tradeoff between the number of blade portions and the area for each individual blade portion, meaning that the number of blade portions and the area for each individual blade portion cannot be increased both at a time, which in turn imposes a limit in possible increase in the pump performance.

In an attempt to improve the above, as disclosed in Patent Document 1 for instance, it has been proposed to prepare a plurality of blade members each having a plurality of blade portions and then to join two blade members to each other, with the respective blade portions thereof being arranged under different states in the circumferential direction. This arrangement is intended to provide increase in the total area of the blade portions for the sake of enhancement of the pump performance.

RELATED-ART DOCUMENT Patent Document

Patent Document: Japanese Unexamined Patent Application Publication No. 2007-40210 (paragraphs [0010] through [0011]).

SUMMARY

However, in the case of the conventional blade member described above, when a plurality of blade members are to be joined to each other, positioning operations of different members are troublesome. Further, if the blade members are joined with an error in their relative position, this can sometimes result in inability for the pump to provide sufficient performance. In the conventional technique above, the joining between the blade members is effected by welding. However, this welding operation per se provides difficulty in quality control, and there is also the risk of such inconvenience occurring from the welded portion due to fatigue during use of the pump.

As described above, with the conventional technique, there remains a problem yet to be solved before a high-performance blade member can be reasonably obtained.

The present invention is provided for overcoming such problems as described above and its principal object is to obtain reasonably a blade member for a pump having superior fluid transporting performance.

[First Characterizing Feature]

According to a first characterizing feature of a blade member for a fluid pump relating to the present invention, the blade member comprises: a cylindrical portion formed around a rotational axis; a plurality of base portions protruding radially outwardly of the rotational axis from one end portion of the cylindrical portion along the rotational axis and provided along a circumferential direction; a bent portion bent from each of the respective base portion in one direction along the rotational axis; and a hole portion provided in a border portion between root portions of the adjacent base portions; wherein a rising edge portion extending from the hole portion to a leading end of the bent portion and an overhang edge portion extending from the hole portion to a leading end of the base portion are formed by a common cut portion.

[Function and Effect]

With the blade member having the above arrangement, a rising edge portion formed in the bent portion and an overhang edge portion formed in the base portion are formed by a common cut portion. This is because cutting and bending of the work are effected simultaneously in the above arrangement. That is, in the overhang edge portion provided in the base portion protruding radially outwards and in the rising edge portion bent from the base portion along the rotational axis, the cut portion of the work will be left as it is. As a result of the above arrangement wherein the cut portion is left as it is in the respective adjacent portions, a plurality of blade portions each consisting of the base portion and the base portion can be arranged with the highest possible density along the circumferential direction. Therefore, it is possible to obtain a highly efficient blade member, either by increasing the number of the blade portions or by securing a larger area for the blade portion.

Also, with the blade member having the above-described arrangement, a hole portion is provided in a border portion between root portions of the adjacent base portions. As a result, during e.g. a bending operation of bending the bent portion from the base portion or rotation of the blade member, concentration of stress at the root portion of the base portion is avoided. In particular, in the case of the present invention, the cutting-raising operation is carried out for cutting/separating the bent portion while raising it from the adjacent base portion at the same time. Therefore, it is possible for the hole portion to prevent the cutting line used in the above from being developed therein excessively toward the cylindrical portion.

[Second Characterizing Feature]

According to a second characterizing feature of a blade member relating to the present invention, the bent portion includes, at a leading end portion of the rising edge portion, a rising leading end edge portion intersecting this rising edge portion; the base portion includes, at a leading end portion of the overhang edge portion, an overhang leading end edge portion intersecting this overhang edge portion; and at the edge portion of whichever shorter one of the rising edge portion and the overhang edge portion, this edge portion and the leading end edge portion intersecting it together form an angle which is an obtuse angle.

[Function and Effect]

In the case of the above-described arrangement wherein a length of the rising edge portion and a length of the overhang edge portion are made different from each other, in the work prior to the cutting-raising operation of the bent portion from the base portion, e.g. the overhang leading end edge portion of the base portion will intersect a position in midway of the rising edge portion of the bent portion. In this situation, since the angle formed between the overhang edge portion in the base portion and the overhang leading end edge portion is formed as an obtuse angle, its exterior angle, that is, the angle formed between the rising edge portion of the bent portion and the overhang leading end edge portion of the base portion is formed as an acute angle. In the case of the blade member of the present invention, the rising edge portion is cut and raised directly from the work. Thus, if the starting position of the cutting-raising operation is formed as an acute angle as described above, the first cut can be easily formed at the time of the cutting-raising operation. Therefore, with the above arrangement, the cutting-raising operation of the work can be effected extremely smoothly.

[Third Characterizing Feature]

According to a third characterizing feature of a blade member relating to the present invention, the length of the rising edge portion is made longer than the length of the overhang edge portion.

[Function and Effect]

With the above-described arrangement of making the length of the rising edge portion longer, in the work prior to the cutting-raising operation, the bent portion protrudes radially outwards relative to the base portion. Namely, the side to form the bent portion is made longer than the side to form the base portion. During formation of the blade portion, the bending operation is initiated and effected progressively from the leading end portion of the bent portion. Therefore, when this bent portion reaches the overhang leading end edge portion of the base portion, the relative velocity between the base portion and the bent portion in a shearing direction has increased to a predetermined velocity. Hence, generation and progress of incision in the work at the cutting-raising starting position can occur easily and the cutting-raising operation can proceed even more smoothly.

[Fourth Characterizing Feature]

According to a fourth characterizing feature of a blade member relating to the present invention, there is set a straight cutting-raising line from the hole portion toward the outer circumference; and when the work is cut and raised by the cutting-raising line, one edge portion forms the rising edge portion and the other edge portion forms the overhang edge portion.

[Function and Effect]

With the above-described arrangement wherein a straight cutting-raising line is set to extend from the hole portion toward the outer circumference and when the work is cut and raised by the cutting-raising line, the rising edge portion of the bent portion along the rotational axis and the overhang edge portion overhung from the hole portion toward the outer circumference can be formed easily.

[Fifth Characterizing Feature]

According to a fifth characterizing feature of a blade member relating to the present invention, the cutting-raising line has a line width smaller than a hole diameter of the hole portion.

[Function and Effect]

With the above-described arrangement of the cutting-raising line having a line width smaller than a hole diameter of the hole portion, it is possible to arrange the blade portions each having the base portion and the bent portion in a high density along the circumferential direction.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] is a front view showing generally a fluid pump using a blade member relating to the present invention,

[FIG. 2] is a side view in section showing generally the fluid pump,

[FIG. 3] is a perspective view showing the blade member relating to the present invention,

[FIG. 4] is a plane view showing the blade member relating to the present invention, and

[FIG. 5] is a plane view showing an outer appearance of a work before blade portions are cut and raised therefrom.

MODES OF EMBODYING THE INVENTION (Brief Outline)

A blade member 1 relating to the present invention is mounted in e.g. a water pump P or the like for use with an engine E of an automobile for example. This blade member 1 includes a cylindrical portion 2 at the center, a plurality of base portions 3 protruding from the cylindrical portion 2 radially outwards relative to a rotational axis X, and a bent portion 4 bent from each one of the base portions 3 in one direction along the rotational axis X, with these mentioned parts being formed integral with each other. The base portion 3 and the bent portion 4 together form a single blade portion H. Next, this blade member 1 will be explained with reference to the drawings.

FIG. 1 shows a water pump P for an automobile including the above blade member 1 as seen from the side of this blade member 1. Further, FIG. 2 is a side view in section showing the water pump P. In a pump body 5 constituting the water pump P, there is mounted via a bearing 7, a rotational shaft 6 to which the blade member 1 is to be attached. The blade member 1 is fixed to the rotational shaft 6 by an appropriate method such as caulking-bolt fastening, welding, etc. At a position of the rotational shaft 6 other than this bearing position, there is attached a sealing member 8 for preventing leak of cooling liquid as a fluid from between the pump body 5 and the rotational shaft 6. Around the blade member 1, there are provided a fluid feeding passage 9 for feeding the fluid to a target portion and a discharge opening 10 for discharging the fluid to the fluid feeding passage 9. Further, around the blade member 1, there is also provided a discharge passage 11 for flowing the fluid in circulation with application thereto of a centrifugal force generated in association with rotation of the blade member 1 in order to cause the fluid to flow toward the discharge opening 10.

Of the terminal ends of the rotational shaft 6, at the one terminal end opposite the side where the blade member 1 is provided, there is provided a pulley 12 for inputting rotation from a crankshaft. The water pump P in this example is a so-called mechanical driven type, so that the water pump P is constantly driven during an operation of the engine E. On the outer side of the seal member 8, there is provided a fluid reservoir chamber 13 for temporarily reserving an amount of cooling water which has leaked to the outside of the engine E. At a position of this fluid reservoir chamber 13 upwardly of a surface of liquid reserved therein, there is formed an opening 14 for allowing evaporation of cooling water reserved in the fluid reservoir chamber 13 to the outside. This prevents soiling of the outer face of the engine E with leaked cooling water. The pump body 5 is fastened to the main body of the engine E with e.g. a plurality of bolts.

The shape of the inventive blade member 1 is illustrated in FIGS. 3 though 5.

At the center position of the blade member 1, there is formed the cylindrical portion 2 which extends in a cylindrical form around the rotational axis X. From one terminal end of the cylindrical portion 2 along the rotational axis X, the plurality of base portion 3 are formed to protrude radially outwards relative to the rotational axis X. These base portions 3 are formed within a plane perpendicular to the rotational axis X and distributed evenly along the circumferential direction. From each one of the base portions 3, a bent portion 4 extends as being bent in the direction of the rotational axis X. This bent portion 4 is a portion for applying, in association with rotation thereof, a centrifugal force to the fluid. This bent portion 4 is gently curved from its side adjacent the rotational axis X toward its outer circumference side. With this, a centrifugal force can be applied to the fluid in an effective manner.

At a border position between adjacent base portions 3, there is formed a circular hole portion 15. This hole portion 15, as will be described later, has a function of preventing excessive development or extension of a cut portion in a work W toward the side of the cylindrical portion 2. Further, during an operation of the water pump P, the hole portion 15 serves to prevent development of fatigue fissure in the cylindrical portion 2 when a repeated bending deformation occurs in the blade member 1.

In the inventive blade member 1, each adjacent pair of blade portions H across the hole portion 15 therebetween are formed in approximate contact with each other. This is because the bent portion 4 is formed by a cutting-raising operation as will be described later. More particularly, prior to a cutting-raising operation of one bent portion 4 thereof, the base portions 3 adjacent thereto are still continuous, i.e. joined integrally. Therefore, under a state after the working/forming of the bent portions 4, the two blade portions H will have respective cut portions which were separated originally from a single component. This characterizing arrangement markedly differs from the conventional arrangement in which a wide punching-out groove portion was formed between adjacent blade portions.

With the inventive arrangement described above, the area of the work W in its entirety can be used as the blade member 1. Hence, it is possible to secure the largest effective area possible for the blade member 1. As particular possible designs of the blade portions, the area of each blade portion H can be increased or alternatively the total number of the blade portions H can be increased. In this way, there is achieved greater degree of freedom in the design of the blade member 1. As a result, it becomes possible to secure a sufficient fluid discharging amount or pressure for the water pump P, whereby the fluid transporting efficiency of the water pump P can be improved. Accordingly, it becomes possible to achieve reduction in power loss of the water pump P by e.g. shortening the radial length of the blade member 1, thus achieving eventually improvement in the fuel consumption efficiency of the engine E.

[Method of Forming Blade Member]

FIG. 5 shows an outer appearance of a work W before the bent portions 4 are cut and raised therefrom. Under this state, the cylindrical portion 2 at the center has already been worked by a drawing operation. Further, eight hole portions 15 in total have also been worked. In FIG. 5, there are shown cutting-raising lines 16 between respective adjacent pairs of blade portions H. It should be noted however that such lines will not be provided in an actually used work W.

The work W presents an approximately octagonal shape. Focusing now on a single blade portion H thereof, there is set a straight or linear cutting-raising line 16 extending from the hole portion 15 toward the outer circumference. After the work W is cut and raised by the cutting-raising line 16, the edge portion on the upstream side in the rotational direction (one edge portion) forms a rising edge portion 18, whereas the edge on the downstream side in the rotational direction (the other edge portion) forms an overhang edge portion 17. These overhang and rising edge portions 17 and 18 are portions which were continuous with each other in the original state of the work W and which are now formed by a common cutting portion. Here, the line width of the cutting-raising line 16 is set smaller than the hole diameter of the hole portion 15. From the outer circumferential end portion of the overhang edge portion 17 toward the rotational downstream side, there is formed an approximately linear, overhang leading end edge portion 19. When the cutting-raising operation is completed, a portion of this overhang leading end edge portion 19 forms a portion of the bent portion 4 and the remaining portion thereof forms a portion of the base portion 3.

On the other hand, from the outer circumferential end portion of the rising edge portion 18 toward the rotational upstream side, there is formed also an approximately linear, rising leading end edge portion 20. When the cutting-raising operation is completed, this rising leading end edge portion 20 forms an edge portion at the leading end portion of the blade member 1 along the axial direction.

For the cutting-raising operation, though not shown, the work W illustrated in FIG. 5 will be set to a molding device for cutting-raising. In this setting, the cylindrical portion 2 will be fixed in position by e.g. mounting it on a projection of a lower mold of the device. Then, an upper mold of the device will be brought into contact with this work W. In this, the upper mold will come into contact with a pressing region 21 which is shown as being encircled with a broken line in FIG. 4 and FIG. 5. Under this state, the rising leading end edge portion 20 will be pushed up toward the upper mold by the lower mold. With this, adjacent base portions 3 which were originally continuous will now be cut and separated from each other and one of them will be bent to form the bent portion 4.

In the above, if the bent portion 4 is bent with forming an approximately perpendicular face relative to the cutting-raising line 16, the working per se of this portion 4 will become easy. Further, the bent portion 4 will be formed with a predetermined curved face for the sake of improvement in fluid transporting efficiency. This curved face will be formed when the lower mold and the upper mold are clamped together to clamp the work W therebetween for forming this bent portion 4.

Referring now in focus to the shape of the work W prior to the cutting-raising operation, as illustrated in FIG. 5, each adjacent pair of base portion 3 and bent portion 4 are formed to have mutually different radial lengths across the cutting portion. With this length differentiating arrangement, a cutout portion 22 can be formed. In the course of this, in addition to the forming of the cutout portion 22, an arrangement is made to render its side of the bent portion 4 longer. With this arrangement, in the course of the cutting-raising operation of the bent portion 4 with pressing by the upper mold and the lower mold, the bent portion 4 will begin to be bent progressively from its leading end portion. And, when this bent portion reaches the overhang leading end edge portion 19 of the base portion 3, a relative velocity between the base portion 3 and the bent portion 4 in a shearing direction has increased to a predetermined velocity. Thus, together with an effect provided by formation of the cutout portion 22, formation and development of incision at the cutting-raising start position can proceed smoothly. Therefore, the cutting-raising operation can proceed even more smoothly.

The angle of the cutout portion 22 will be formed as an acute angle for facilitating formation of an incision. To this end, in the instant embodiment, the angle of the corner portion which is to form the base portion 3 is formed as an obtuse angle. As illustrated in FIG. 5, provided the portion to form the edge portion on the side of the bent portion 4 after cutting constitutes the rising edge portion 18 and the edge portion on the side of the base portion 3 constitutes the overhang edge portion 17, in the instant embodiment, the length of this overhang edge portion 17 is set longer than the length of the rising edge portion 18. For formation of the cutout portion 22, the two edge portions should have unequal lengths. In this particular case, the length of the rising edge portion 18 is set longer in order to obtain a greater area for the bent portion 4.

As a result of the above-described arrangement, the angle formed between the overhang edge portion 17 and the overhang leading end edge portion 19 extending in the intersecting direction from this overhang edge portion 17 is formed as the obtuse angle.

Incidentally, from the leading end of the rising edge portion 18, there is formed a rising leading end edge portion 20 which extends from this rising edge portion 8 in its intersecting direction. When the bent portion 4 is cut and raised, this rising leading end edge portion 20 forms an edge portion on one side along the rotational axis X. With appropriate setting of the angle formed between the rising edge portion 18 and the rising leading end edge portion 20, an inclination angle 23 (see FIG. 2) of the rising leading end edge portion 20 when the completed blade member 1 is viewed in a direction at right angle relative to the rotational axis X can be set to a predetermined angle. This inclination angle 23 becomes important in specifying the shape of a fluid communication space when a wall portion adjacent the blade member 1 is to be formed on the side of the engine E for instance. The inclination angle 23 is set to an optimal value, depending on the size of the blade member 1, the direction fluid transported, the viscosity of the fluid and/or the rotational speed of the blade member 1, etc.

Incidentally, in FIG. 5, the rising leading end edge portion 20 is formed straight. However, this can also be curved so that the inclination becomes progressively more gentle on the radially outer side in the completed blade member 1.

INDUSTRIAL APPLICABILITY

The blade member of the present invention is applicable as a blade member for various kinds of fluid pump such as a water pump for use with an engine of an automobile. 

1. A blade member for a fluid pump, comprising: a cylindrical portion formed around a rotational axis; a plurality of base portions protruding radially outwardly of the rotational axis from one end portion of the cylindrical portion along the rotational axis and provided along a circumferential direction; a bent portion bent from each of the respective base portion in one direction along the rotational axis; and a hole portion provided in a border portion between root portions of the adjacent base portions; wherein a rising edge portion extending from the hole portion to a leading end of the bent portion and an overhang edge portion extending from the hole portion to a leading end of the base portion are formed by a common cut portion.
 2. The blade member for a fluid pump according to claim 1, wherein: the bent portion includes, at a leading end portion of the rising edge portion, a rising leading end edge portion intersecting this rising edge portion; the base portion includes, at a leading end portion of the overhang edge portion, an overhang leading end edge portion intersecting this overhang edge portion; and at the edge portion of whichever shorter one of the rising edge portion and the overhang edge portion, this edge portion and the leading end edge portion intersecting it together form an angle which is an obtuse angle.
 3. The blade member for a fluid pump according to claim 2, wherein the length of the rising edge portion is made longer than the length of the overhang edge portion.
 4. The blade member for a fluid pump according to claim 1: wherein: there is set a straight cutting-raising line from the hole portion toward the outer circumference; and when the work is cut and raised by the cutting-raising line, one edge portion forms the rising edge portion and the other edge portion forms the overhang edge portion.
 5. The blade member for a fluid pump according to claim 4, wherein the cutting-raising line has a line width smaller than a hole diameter of the hole portion. 